Investments - Market Value, Cost, and Unrealized Gain or Loss on Investments (Detail) (USD $)	Dec. 31, 2013		Jun. 30, 2013
Amortized Cost And Fair Value Debt Securities [Abstract]
Trading, market value	$ 18,640,758		$ 4,758,220
Available-for-sale, market value	7,343,679		9,053,111
Total investments, market value	25,984,437		13,811,331
Trading, cost	19,062,335		5,457,989
Available-for-sale, cost	6,485,471		8,064,902
Total, cost	25,547,806		13,522,891
Trading, unrealized gain (loss)	(421,577)	[1]	(699,769)	[1]
Available-for-sale securities, unrealized gain (loss)	858,208	[2]	988,209	[2]
Total, unrealized gain (loss)	436,631		288,440
Available-for-sale, unrealized holding gains on available-for-sale securities	$ 566,417		$ 652,218

[1] Unrealized and realized gains and losses on trading securities are included in earnings in the statement of operations.

[2] Unrealized gains and losses on available-for-sale securities are excluded from earnings and recorded in other comprehensive income as a separate component of shareholders’ equity until realized.